Defense secretary Robert Gates says that the program changes he proposed last week reflected the need to "rebalance" the nation's military posture in light of recent operational experience. That is only half right. They also reflect the fact that five percent of the world's population -- the United States -- can no longer afford to sustain nearly fifty percent of global military outlays. Not when our economy’s share of global output is declining every year and our government is spending five billion dollars each day that it does not have. You know you're out of money when the only way left to sustain your defense posture is by borrowing money from the biggest military power you might have to fight in the years ahead.

So it shouldn't come as a surprise that the only real reason for canceling the F-22 fighter advanced by the Secretary and Chief of Staff of the Air Force in an April 13 Washington Post essay was that "buying more F-22s means doing less of something else." The Air Force officials correctly state that defense budgeting has become a "zero-sum game" -- a situation likely to persist as President Obama focuses on domestic initiatives and deficit reduction.

But just because the spigot has been turned off at the Pentagon doesn't mean the Gates spending priorities are right. Here are four ways they could be wrong.

--Defective Forecasts.
Gates echoes the President in saying we "must enhance our capabilities to fight the wars we are in today and the scenarios we are most likely to face in the years ahead." Unfortunately, U.S. policymakers have been notoriously bad at forecasting future threats. Think of all the surprises of recent history -- the attack on Pearl Harbor, North Korea's invasion of the South, Sputnik, the Cuban missile crisis, the Tet Offensive, the collapse of communism, 9-11, etc. The record says we seldom know what's coming next, so basing our defense posture on the belief that we do isn't smart.

--Diminished Deterrence.
Gates clearly doubts the need for a new air-superiority fighter, since he wants to end F-22 production at a number far below any analytically-derived force objective. He also says the Air Force won't need a new bomber anytime soon, and that the Navy can get by with only ten aircraft carriers (a level that arrives in 2012, not 2040). Isn't it likely the reason we feel so unthreatened today by the forces of other nations is because our weapons deter aggression so effectively? So what happens when our weapons cease to impress? Other nations will respond to U.S. cuts by becoming bolder.

--Additional People.
Gates apparently believes that future threats require a more labor-intensive military posture. So the number of military and civilian personnel in the defense department will increase, while investment in technology will decline. The new mix promises to be very costly over the long run, since the government's commitment to personnel involves pay and benefits averaging $100,000 per person per year that extend decades into the future. If you think weapons costs are up, check out military healthcare -- up 144% in eight years! Why do we need all the new personnel if we're getting out of Iraq?

--Exaggerated Danger.
Gates thinks the reason the services want so many sophisticated weapons is because they have an exaggerated idea of the conventional threats they will face in the future. Well what about his own assessment of unconventional threats? Do we really need to retool our whole defense posture to cope with pirates, narco-terrorists and religious zealots? After eight years of fighting a “global war on terror,” the accumulated U.S. casualties are about the same as were suffered by both sides in the three-day Battle of Gettysburg in 1863 -- and that's counting the civilian losses on 9-11.